git-rev-list.txt: move description to separate file

A following commit will reuse the description of the `git rev-list`
command in the `git log` manpage.

Move this description to a separate file.

Signed-off-by: Philippe Blain <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: phil-blain

Documentation/git-rev-list.txt

@@ -14,44 +14,7 @@ SYNOPSIS
 DESCRIPTION
 -----------
 
-List commits that are reachable by following the `parent` links from the
-given commit(s), but exclude commits that are reachable from the one(s)
-given with a '{caret}' in front of them.  The output is given in reverse
-chronological order by default.
-
-You can think of this as a set operation. Commits reachable from any of
-the commits given on the command line form a set, and then commits reachable
-from any of the ones given with '{caret}' in front are subtracted from that
-set.  The remaining commits are what comes out in the command's output.
-Various other options and paths parameters can be used to further limit the
-result.
-
-Thus, the following command:
-
------------------------------------------------------------------------
-$ git rev-list foo bar ^baz
------------------------------------------------------------------------
-
-means "list all the commits which are reachable from 'foo' or 'bar', but
-not from 'baz'".
-
-A special notation "'<commit1>'..'<commit2>'" can be used as a
-short-hand for "^'<commit1>' '<commit2>'". For example, either of
-the following may be used interchangeably:
-
------------------------------------------------------------------------
-$ git rev-list origin..HEAD
-$ git rev-list HEAD ^origin
------------------------------------------------------------------------
-
-Another special notation is "'<commit1>'...'<commit2>'" which is useful
-for merges.  The resulting set of commits is the symmetric difference
-between the two operands.  The following two commands are equivalent:
-
------------------------------------------------------------------------
-$ git rev-list A B --not $(git merge-base --all A B)
-$ git rev-list A...B
------------------------------------------------------------------------
+include::rev-list-description.txt[]
 
 'rev-list' is a very essential Git command, since it
 provides the ability to build and traverse commit ancestry graphs. For

Documentation/rev-list-description.txt

@@ -0,0 +1,38 @@
+List commits that are reachable by following the `parent` links from the
+given commit(s), but exclude commits that are reachable from the one(s)
+given with a '{caret}' in front of them.  The output is given in reverse
+chronological order by default.
+
+You can think of this as a set operation. Commits reachable from any of
+the commits given on the command line form a set, and then commits reachable
+from any of the ones given with '{caret}' in front are subtracted from that
+set.  The remaining commits are what comes out in the command's output.
+Various other options and paths parameters can be used to further limit the
+result.
+
+Thus, the following command:
+
+-----------------------------------------------------------------------
+$ git rev-list foo bar ^baz
+-----------------------------------------------------------------------
+
+means "list all the commits which are reachable from 'foo' or 'bar', but
+not from 'baz'".
+
+A special notation "'<commit1>'..'<commit2>'" can be used as a
+short-hand for "^'<commit1>' '<commit2>'". For example, either of
+the following may be used interchangeably:
+
+-----------------------------------------------------------------------
+$ git rev-list origin..HEAD
+$ git rev-list HEAD ^origin
+-----------------------------------------------------------------------
+
+Another special notation is "'<commit1>'...'<commit2>'" which is useful
+for merges.  The resulting set of commits is the symmetric difference
+between the two operands.  The following two commands are equivalent:
+
+-----------------------------------------------------------------------
+$ git rev-list A B --not $(git merge-base --all A B)
+$ git rev-list A...B
+-----------------------------------------------------------------------